The reason that dips are in runways is because there is absolutely no way for the workers to get them perfectly level. It does not affect perfomace and you usually see the dips in the much longer runways and the short ones only deviaite by about a foot or two.

well if the ground is flat already, it won't dip. if it is hilly it will be too expensive to elevate it to keep it level. by the way, the runway in this pic is 75 feet wide (you can tell b/c there are 6 threshold stripes)

it doesn't matter ... like do hills effect your driving on a highway. When the jet is careening down the runway all that matters is relative speed and whether the runway is long enough (LOL). As long as the "dips" are not trenches and the wheels ride smooth, the plane encounters no loss or gain in performance.

There is actually a picture in Airliners mag, I think an Iceland issue where there is a little runway (one of the shortest in the world or something) and it looks like a U. serious. check it out.

Kona airport in Hawaii has a dip in the runway, you dont even notice it unless you look at it. Also, Kona airport is very interesting because when you fly in there you are expecting some real nice grass and stuff, but you fly in there and there is nothing but lava fields and little chunks of grass growing through the little cracks.

You can't see the threshold strips in that picture, I'm assuming you're talking about the one posted by Britishmidland (second post in the thread). The three stripes you can see in the foreground are touchdown-zone markings, not threshold markings.

In Istanbul Ataturk Airport (LTBA) there is a dip in 06/24 runway. This dip is used for stopping aircraft. But it can be dangerous during rainy days. Because of water in this section. The pilot can find himself and the aircraft in hydroplanin conditions.

During the takeoff roll, the aircraft accelerates. When it gets to the downward slope of the dip, it accelerates even quicker. And when it gets to the other side (upward), it helps the aircraft rotate and fly into the sky.

This has been discussed not long ago, so I guess you can use the search function to find your answer.

There is a significant dip in the runway (when viewed from the end) at the Tallahassee Regional Airport in Tallahassee, FL (TLH) which is a fairly small airport handling mostly 737 & md80 types. I also noticed a dip on the north side runway at ATL (26R I think) when I took off and it did not affect the ride.

Antigua's airport (ANU, Vere Bird International) has a significant dip in its main runway. It is visible as you taxi along the taxiway and as you turn onto the threshold for take-off. The same is also true for Tobago (TAB, Crown Point International). I have wondered about this too.